Hi Sashank,
My recommendation for you would be to focus exclusively on Official GMAT material in the last leg of your preparation. Do not take any more
MGMAT tests as a low score on these will demotivate you and create more anxiety since there's not much time left. If you've already taken the
MGMAT tests, I'd recommend you use the analysis of your tests to figure out your weak areas and work on improving in those specific areas by practising questions from the OG.
Make sure that you are able to tackle every single question from the OG with ease. You should at least be familiar with all the question types there. Solve these questions in a timed setting, and make sure you properly review all the questions you get wrong.
Once that's done, you should also download the GMAT Prep software from mba.com and take those tests. Review all the questions you get wrong and make sure you do the tests multiple times so that you squeeze maximum the questions out of the software.
If you have finished all of this and still have 1-2 weeks before the GMAT exam, you might want to consider getting the GMAT Exam Pack 1 or Question Pack 1 that's available on mba.com.
Doing this will completely familiarize you with the way Official GMAT questions are phrased and you will be more comfortable tackling them on test day because of your focus on similar questions leading up to test day.
Good luck with your prep and let me know how it goes!

Cheers.